Green computing is sometimes defined as the study and practice of using computing resources efficiently. Typically, technological systems or computing products that incorporate green computing principles take into account economic viability, social responsibility, and environmental impact. One major goal of green computing as applied to printing apparatuses is to create smaller carbon footprints, allowing the least amount of greenhouse gases to be produced and released into the environment from printing operations.
Various types of printers are widely used in offices and homes around the world and they have become standard indoor electronic equipment. Toner-based printers, like laser printers, are commonly used. These printers work by using precision lasers to adhere toner to a light-sensitive print drum, then using static electricity to transfer the toner to the printing medium to which it is fused with heat and pressure. Laser printers are known for high quality prints, good print speed, and low cost. Toner, though, contains a large number of volatile and semi-volatile organics.
Additionally, solid ink printers are also commonly used. In some formats, a printhead sprays ink from solid-colored ink sticks onto a rotating, oil coated drum. The paper then passes over the print drum, and the image is transfixed, to the page. Solid ink printers are excellent at printing on transparencies and other non-porous media. Acquisition and operating costs are similar to laser printers, but these printers have high power consumption rates, particle emissions, and long initialization periods.
Inkjet printers, on the other hand, have a much smaller carbon footprint. These printers consist of nozzles that produce very small ink bubbles that turn into tiny droplets of ink. The dots formed are the size of tiny pixels and are adhered to paper in a liquid form. Ink-jet printers can print high quality text and graphics and are used for both black-and-white and color printing. They also have a much lower initial cost than do laser printers, but have a much higher cost-per-copy, as the ink cartridges need to be frequently replaced. Additionally, inkjets are far slower than laser printers and have the disadvantage that pages must be allowed to dry before being aggressively handled; otherwise, the liquid ink will smear.
No matter the type of printers used, many indoor office environments utilize network printing, a method that enables users in locations geographically separate from each other and from their print devices to produce documents for themselves and others. Print servers enable multiple clients to share one or more print devices and where there are several busy printers and many clients, a central print spool is generally implemented. With a central print spool, print jobs are received from all clients and then dispatched to an available printer. Present print spool configurations commonly look only for available printers; they do not modify printer availability based on the characteristics of the individual printers.
Generally, energy consumption and resource utilization are not optimized when a computer may print to a plurality of printers with varying energy consumption rates, warm up times, paper selections, and other attributes. Without such optimization, energy and resources are wasted.